loose puch thrust bolt

My '78 puch maxi stopped running after something vibrated terribly inside the one speed transmission. I've taken off the transmission cover and noticed the thrust bolt is loose, causing the spring ring to loosen within the retaining spring. Is the thrust bolt supposed to be loose? Did something rupture inside of the engine? help!

Re: loose puch thrust bolt

Gregory Mcintire /

What do you mean by the "thrust bolt" and "spring ring" and "retaining spring"? I can't find any parts in the service manual with those names.

The only part that I can think of that should be "loose" is the starter clutch pressure plate (large round disk, retained by a large spring steel wire circlip). Also the small bearing assembly in the center of that disk should spin freely.

Or are you refering to the cam assembly that accuates the starter clutch?

Re: loose puch thrust bolt

Joel Horowitz /

I'm referring to the following link as far as the terminology goes. http://www.themopedjunkyard.com/puchtransmission.html

And when i mean 'loose' i mean that the spindle/thrust bolt moves from side to side and up/down allowing the plate to moves as well rather than spinning perfectly centered.

Re: loose puch thrust bolt

Tab Patterson /

I think that's normal. Mine does the same... Fortunately, those parts are easy to find.

Re: loose puch thrust bolt

Gregory Mcintire /

The large diameter retaining ring (#13 in the diagram) should fit securely into the groove in the clutch drum (#4) but the clutch plate normally is able to to wiggle around a bit. I just looked at the thrust bolt in two engines I have apart and they are both fairly loose.

Re: loose puch thrust bolt

Joel Horowitz /

okay, I just put everything back together and i've realized that a bearing must've definitely ruptured inside of the engine. I found some pieces of crushed something or other inside of the magneto, and when i spin the engine, i hear a grinding noise.

how big of a problem is this?

Re: loose puch thrust bolt

have you pulled the flywheel off? it is possible that the crushed stuff is key, or keyway, that would cause the problems you are having

Re: loose puch thrust bolt

Joel Horowitz /

i'm quite the layman when it comes to this...i purchased it a few months ago, had a lot of fun riding it around, then got bummed out when it stopped running.

anyway, i've no idea what keys are. sorry. could you explain?

thanks so much,

joel

Re: loose puch thrust bolt

the flywheel slides over the crankshaft, to make it spin with the crankshaft there is a sloted piece if metal(key) that fits into the slot in the crankshaft(keyway) and a slot in the flywheel, if the bolt on the flywheel comes a little loose the flywheel likes to eat up the key and keyway, that would make a grinding sound, and cause the bike to stop running, it would also leave some ground up something in the magneto

Re: loose puch thrust bolt

Joel Horowitz /

I messed around with it last night, and i know the problem definitely lies within the magneto. Something is rubbing and grinding - and it could very well be the key thing you mentioned. I just can't seem to get the flywheel off. I removed the bolt attaching the flywheel, but I'm not able to pry the flywheel off at all.

I know, I'm a moron. I downloaded the manual and theres no mention to detaching the flywheel. Do I need a special tool? I didn't use the special spanner to remove the bolt - I just jammed it with a screwdriver (without damaging anything inside).

thanks

Re: Flywheel removal

yes, there is a tool to pull fly wheel.

Or just do, what I've been doing for years ,SEE PIC

remove crank nut.

using a flat screwdriver cut edge of case rim,as in pic, so a flat screwdriver can fit behind flywheel,

with "LIGHT" pressure behind flywheel,(Don't pry on it hard) "LIGHTLY TAP" on center of FLYWHEEL >>>NOT THE CRANK<<< and flywheel should pop right off real easy.

as for the KEYWAY it's on the crank that the nut was on, it's a little 1/2 moon looking piece of metal that sits flat side up ,that is what keeps the flywheel in line with the crank, look at the inside of flywheel crank hole at the notch if it looks worn out(not straight) you have a major problem.

Now, when reinstalling flywheel, I make sure the piston is TDC and and points are open on high point of flywheel ,line up keyway to flywheel and slide on to crank Make sure it's on correct b-4 you install crank nut.Good Luck!

1089125432_flywheelnotch.jpg

Re: Flywheel removal

Joel Horowitz /

i don't have a notch like that in my case rim! weird.

Re: Flywheel removal

that's cause, I made the notch,with a screwdriver.

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